Blacktop vs. Concrete

[Mergingtraffic]

I ponder the question, why the northeast states repaved most of their interstates with blacktop when concrete seems to last longer?

States such as NY  and CT started to repave their interstates over with asphalt starting in the 80s and 90s.  Since then cracks appear within a couple of years and in some cases have to be repaved 10 years later.

Meanwhile there are concrete sections of highway that have never been repaved and are still fine.

Example:
I-84 in Manchester CT is still cement and the DOT will be smoothing out the cement instead of repaving it over with asphalt. So in 40 years this is the first time it will be "repaved" and I'm sure it will last another 40 years before it has to be done again.

[J N Winkler]

There are many considerations governing the choice between Portland cement concrete and asphaltic concrete (where high-type pavements are concerned, both "cement" and "asphalt" are really different types of concrete), but in general it comes down to which type provides the most benefit relative to cost for a given location.

*  Because PCC lasts so long, it can create a problem of excess durability.  It is not, for example, a very good investment to lay fresh PCCP down on a road which is expected to need widening sometime in the next 10 years or so because the investment won't produce returns at the far end of its natural lifetime.  On the other hand, if you expect a road not to need widening or reconstruction for a period ranging from 40 years to forever, it can pay to lay down a PCCP (designed for indefinite durability) since the high initial cost will be recouped over a very long period.

*  First cost of either type of pavement can be influenced by availability of raw materials.  For example, in the period of first Interstate construction, most of I-70 in Kansas west of Salina was paved in asphalt because aggregates for Portland cement concrete were in short supply in western Kansas.  On the other hand, when the price of oil (the input material for asphalt binder) goes up, this tends to tilt calculations in favor of Portland cement in marginal cases.

There are many other factors that can be considered and can be incorporated into cost-benefit analysis, but are too much to go into here--I'd suggest Roland McKean's Efficiency in government through systems analysis as a good general guide to the issues that are involved.

[1995hoo]

From what I've read, asphalt is usually cheaper during the construction phase even though in the long term it winds up costing more. Many governments' regulations these days mandate using the cheapest means of construction, even though that's short-sighted if it winds up costing more in the long term. (The debate in the DC area about putting the Metrorail in a tunnel or on an elevated structure through Tysons Corner is a well-publicized recent example of this argument.) Concrete repair costs more and is somewhat more complex, even if it's less likely to need repair. Finally, some places with particularly bad weather are known to be less likely to use concrete because it provides somewhat less traction in rain and snow. I saw an article talking about road-paving in Colorado that mentioned that they prefer asphalt for the mountain roads because its higher heat absorption (inherent in black surface versus white surface) helps a bit with melting snow and ice.

No doubt public opinion factors in as well. While many newer concrete surfaces are reasonably quiet and smooth, almost everyone's encountered older ones where the surface is coarse and noisy and the joints are far more noticeable than they are on asphalt roads so you get that "clopping" sound as you cross each one (or, as my brother once said, it feels like you're driving down a flight of stairs). I know quite a few people who profess to hate concrete roads because of noise. If their experience with them comes from I-66 between Fair Oaks Mall and the Beltway or with some of the older concrete roads in Maryland, then I understand their opinion, but I'd encourage those people to drive on I-66 west of Fair Oaks Mall or on US-50 between DC and Annapolis and then reconsider their comments.

[agentsteel53]

Many governments' regulations these days mandate using the cheapest means of construction, even though that's short-sighted if it winds up costing more in the long term.

why not just smear some feces on the side of a hill and call it a road, then?  that's cheaper.

[vdeane]

Probably because they can just slap a layer of asphalt on the highway and claim they did something without actually repairing the road.  There are several sections of highway in NY that need total reconstruction but instead just get patched over with asphalt every 10 years.

No doubt public opinion factors in as well. While many newer concrete surfaces are reasonably quiet and smooth, almost everyone's encountered older ones where the surface is coarse and noisy and the joints are far more noticeable than they are on asphalt roads so you get that "clopping" sound as you cross each one (or, as my brother once said, it feels like you're driving down a flight of stairs). I know quite a few people who profess to hate concrete roads because of noise. If their experience with them comes from I-66 between Fair Oaks Mall and the Beltway or with some of the older concrete roads in Maryland, then I understand their opinion, but I'd encourage those people to drive on I-66 west of Fair Oaks Mall or on US-50 between DC and Annapolis and then reconsider their comments.

But I LOVE that sound!

[mtantillo]

Also, lets not forget considerations of traffic control when paving with concrete vs. asphalt.  Asphalt can be applied overnight, and the lanes opened up in time for the next day, while concrete often requires more extended lane closures.  Depending on the nature of the roadway, this could be done over a weekend, but some roads have enough weekend traffic and few alternate routes so this is just not possible. 

The best example I can think of is the Cross Bronx Expressway.  The pavement is in horrible shape because of all the heavy truck traffic starting and stopping on it (that's why they typically put concrete pads where heavy vehicles start and stop, like bus stops or weigh stations), its cracked, rutted, etc.  Seems like a perfect candidate for concrete pavement.  Unfortunately, there is only a tiny window of time (maybe a few hours in the wee hours of the night) where you can close down any lanes without causing all of NYC to be in absolute gridlock, and weekend traffic is just as bad as weekday traffic...and there's no shoulder to be used to allow for lane shifts...and the bridge piers come way too close to the roadway to allow using any kind of zipper wall/express lane configuration.....and that means you have to repave in asphalt quite frequently.

[roadfro]

Another consideration is the type of climate the pavement will be laid in. In desert climates, one has to look at the type of asphalt & binders used and whether that will stand up to desert heat. Asphalt is more flexible, and is more succeptible to rutting when temperatures are high and traffic loads are heavy (especially if there's lots of braking, like at an intersection)--see some intersections around the Vegas area for bad rutting examples. PCC doesn't have this problem, but if conditions are right and there's some problem, the slabs can blow out in hot weather (as discussed in another thread).

Designers will typically do a cost-benefit analysis over a time span of 30-50 years or so. (At least, this is what I learned in a pavement design course several years back.) Asphalt is cheaper initially, but typically requires overlays and other preventative maintenance every 8-10 years (depending on the mix design). Taking the initial costs plus preventative maintenance out that far, sometimes PCC will win out over AC. The points JN Winklyer brought up, as far as what future traffic demands, road expansion possibilities, and availability of materials, also play an important part in the cost-benefit analysis.

[1995hoo]

Many governments' regulations these days mandate using the cheapest means of construction, even though that's short-sighted if it winds up costing more in the long term.

why not just smear some feces on the side of a hill and call it a road, then?  that's cheaper.

If you did that, you'd have I-66 between Fair Oaks and the Beltway!

[Crazy Volvo Guy]

Ooooh this is my thread!

I personally think the advantages of PCC almost universally outweigh the benefits.

As for the future widening issue, existing concrete pavement doesn't necessarily have to be torn out to facilitate that.  I've been plenty of places where I drove down a road and it was blatantly obvious that it had originally been done in PCC then it was widened, as the outer or inner lanes depending on which way they widened (inward or outward) were also PCC but pretty obviously newer.

While we're discussing concrete, I used to like the whine noise "newer" PCC pavements used to make, but now it seems in the newest ones, they've started to randomize the grooves so it doesn't whine anymore - well they got what they wanted there, but I don't think they quite achieved their desired effect, as most of them now just make a real loud and ugly sound that's notably louder and more annoying than the whine was.  Seeing as how I actually liked the whine, that really irritates me.

Heading south on I-65 south of Louisville, you have a rare opportunity to study all four current major types of pavement.  You go from diamond-ground concrete to transverse grooved concrete to longitudinal grooved concrete to asphalt.  I recently had to drive that entire stretch in an incredible rainstorm.  My observation is that diamond ground surfaces are HORRIBLE in the rain and worn asphalt is about as bad especially where rutted by heavy truck traffic as the water pools up in the ruts, while transverse grooved concrete disperses the water amazingly well and longitudinal grooved concrete is almost as good.

I can't understand New England's aversion to it.  The upper midwestern states use it extensively with no major issues, their temperatures hit worse extremes than just about anywhere in New England.

It's also a great way to reduce dependence upon oil, since it's not a direct component of the pavement like it is asphalt. (Ever wondered why fresh asphalt STINKS so bad?)  Additionally, it takes less energy to properly illuminate it at night.

Asphalt may be quiet, smooth and good-looking when it's first put down, but it deteriorates far quicker.  Down here in the hot, sunny climates, it loses that fresh new look in about a month.

[Riverside Frwy]

Ashpalt would be no problem if our roads got proper funding. Notice you rarely see a European Motorway that has concrete, yet they still look amazing because they have funding to be rehabilitated when needed.

New Cement done right can look just as nice though, and I think we can all agree that pavement doesn't look pretty when it's been beat up for years, cement or asphalt.

[Scott5114]

Kansas has been reconstructing I-35 from Emporia to Kansas City in concrete for the past decade or so. It's the best-quality road I've ever driven on. Looking forward to tackling it for the first time at 75 MPH next week.

[Crazy Volvo Guy]

Ashpalt would be no problem if our roads got proper funding. Notice you rarely see a European Motorway that has concrete, yet they still look amazing because they have funding to be rehabilitated when needed.

New Cement done right can look just as nice though, and I think we can all agree that pavement doesn't look pretty when it's been beat up for years, cement or asphalt.

I don't really understand Europe's aversion to concrete either.  Yeah, all the European motorways look great because they repave them ALL THE TIME.  That's just too much and too frequent of an interruption to the flow of traffic.  Just do it concrete and snarl traffic once every 25 years for pete's sake.

[agentsteel53]

I think we can all agree that pavement doesn't look pretty when it's been beat up for years, cement or asphalt.

yes it does.



you don't want to drive this road at more than 45mph or so, but it sure does look pretty.

[wytout]

I ponder the question, why the northeast states repaved most of their interstates with blacktop when concrete seems to last longer?

States such as NY  and CT started to repave their interstates over with asphalt starting in the 80s and 90s.  Since then cracks appear within a couple of years and in some cases have to be repaved 10 years later.

Meanwhile there are concrete sections of highway that have never been repaved and are still fine.

Example:
I-84 in Manchester CT is still cement and the DOT will be smoothing out the cement instead of repaving it over with asphalt. So in 40 years this is the first time it will be "repaved" and I'm sure it will last another 40 years before it has to be done again.

I often thought the cement in Manchester was original, but it's not.  I 84 went through major reconstruction throughout the 1980's there adding HOV lanes, which are also concrete.  This cement section in Manchester That still remains was poured in the 1980's, probably one of the last times the state used concrete.  Though it's not original to the "Wilbur Cross Highway", it has still held up over 25 years, unlike the asphalt which seems to be in perpetual rotating sections of "milling and paving" every 5 years.

[Crazy Volvo Guy]

I often thought the cement in Manchester was original, but it's not.  I 84 went through major reconstruction throughout the 1980's there adding HOV lanes, which are also concrete.  This cement section in Manchester That still remains was poured in the 1980's, probably one of the last times the state used concrete.  Though it's not original to the "Wilbur Cross Highway", it has still held up over 25 years, unlike the asphalt which seems to be in perpetual rotating sections of "milling and paving" every 5 years.

The fact that it's held up so well has me scratching my head as to why CT no longer uses it.  I went through CT more times than I could count in the 15 years I lived in NH, and while the asphalt sections are always deteriorating and being rehabilitated, the concrete segment in Manchester has never really needed much of anything as far back as I can recall.

[CL]

Concrete is so much more worth it than asphalt. There's a three-mile stretch of I-80 in Salt Lake that's still has the original concrete from 1966. It's not the quietest ride on that pavement, but UDOT maintains the concrete well so it's at least a smooth ride. What's also nice about it is that all new concrete in the state is noiseless. Smoothest, quietest ride ever.

[wytout]

There is a lot of short-sightedness with regards to surface materials.  Obviously the asphalt is cheaper and has a much faster cure time, but to me the long term costs must actually be higher, because the asphalt needs to be milled and repaved so frequently.  I think I'd rather have a highway closed 1 lane at a time for several days for concrete to cure once every 30 years, then have to go through resrufacing zones every 5 years on the same stretch of road.  Even the older concrete that isn't too quiet still seems to give a generally uniform tolerable ride.  

Moving away from concrete in favor of asphault is the same as everyting else and can be summed up with one simple cliche :  They sure don't make things like they use to.

This is not only true when discussing asphalt vs. concrete.  It's also true with regards to 30 year old asphalt vs. today's asphalt.
Case in point: My grandparents driveway is a large square 3 cars wide, 2 deep.  It was paved w/ asphalt years before I was born.  It was fine without more than a crack or two until I was about 25.  They had to have the driveway turn up do to a sewer line about 6 years ago.  My grandfather was adamant that the base materials be properly packed in to that when the driveway was repaved, again it would hold up for years.  Well it was repaved about 8 years ago... it's flat, good base, but it's got about a million cracks in it. 

My Point:
CONCRETE > ANY ASPHALT
YESTERDAYS ASPHALT > TODAYS ASPHALT
TODAYS ASPHALT IS PURE GARBAGE.

[Brandon]

In Illinois, it used to be dictated by the construction lobby. 

[Riverside Frwy]

I think we can all agree that pavement doesn't look pretty when it's been beat up for years, cement or asphalt.

yes it does.



you don't want to drive this road at more than 45mph or so, but it sure does look pretty.

Sorry, but pretty scenery doesn't make I-80 through the sierras look or feel any less $hitty.

[vdeane]

Didn't know I-80 was a two lane road with a double yellow line.

[Riverside Frwy]

Didn't know I-80 was a two lane road with a double yellow line.

No, the point he was making(atleast that is what I took from it) is that pretty scenery makes crappy pavement look better. That is obviously the picture is not I-80, I was just saying I-80 has pretty scenery too while it travels through the sierras, but that doesn't change the fact it has crappy pavement.

[hobsini2]

Alot of the problems from state to state is that each state uses a different chemical compound for asphalt.  Illinois for example likes to use a dirt cheap mix that needs to be resurfaced about every 4 years.  Part of the problem is also the type of salt used for snowplowing that eats up the road quickly.  The city of Naperville for example has resurfaced Washington St at least 3 times now in the last decade.  I think concrete lasts longer.  The roads in Wisconsin that use the concrete don't seem to need to be reconstructed more than once every 10-15 years and sometimes even longer.  I wish though when we build major highways, we would do what the Germans do.  The Autobahns are built to last almost double that of American roads because the foundations are much thicker.

[Mergingtraffic]

I often thought the cement in Manchester was original, but it's not.  I 84 went through major reconstruction throughout the 1980's there adding HOV lanes, which are also concrete.  This cement section in Manchester That still remains was poured in the 1980's, probably one of the last times the state used concrete.  Though it's not original to the "Wilbur Cross Highway", it has still held up over 25 years, unlike the asphalt which seems to be in perpetual rotating sections of "milling and paving" every 5 years.

The fact that it's held up so well has me scratching my head as to why CT no longer uses it.  I went through CT more times than I could count in the 15 years I lived in NH, and while the asphalt sections are always deteriorating and being rehabilitated, the concrete segment in Manchester has never really needed much of anything as far back as I can recall.

In fact, the DOT smoothed out the concrete on I-691 and it's so smooth. In fact I actually think it speeds up the mph b/c it's so smooth.

I think to find out the reason the state DOT paved over all the concrete we would have to ask the guys that were in charged back in the 80s and 90s.  Today, the DOT seems ready to preserve the remaining concrete sections as there are plans to preserve the concrete on CT-25 (as well as take out the odd slow vehicle lanes on a flat portion of road), as well as I-84 in Manchester.

[Crazy Volvo Guy]

Been on 691 many times, even have some pics from that stretch from about 2004 or so.

What about I-84 in Waterbury?  Or is that too far gone?  It doesn't seem to be cracked, just a rough pour.

[kurumi]

I do remember sometime in the 1990s when CT was replacing several blocks of PCC on the northeastern section of I-84. A lane or two was blocked off for miles as workers dug into the concrete. Brought back non-fond memories of Pennsylvania where miles and miles of I-80 and I-81 were single-lane because of this type of rehabilitation.